V40 intermittent brake problem

[techie]

Sometimes when I start my v40 and shift it into drive car start moving
forward brakes are not working. Brake pedal is hard and it takes almost
10m distance to stop the car, it keeps creeping forward.

After 5 min or so, brakes would start working normally. This problem
only happens once in a while. I was not able to find any dependency on
the weather, etc ... I took car to the dealership and they didn't find
anything wrong with break system.

Did anybody have similar problem? I hope it will not happen again but
at 100 km/h ....

 

[Lloyd Wells]

Sometimes when I start my v40 and shift it into drive car start moving
forward brakes are not working. Brake pedal is hard and it takes almost
10m distance to stop the car, it keeps creeping forward.

After 5 min or so, brakes would start working normally. This problem
only happens once in a while. I was not able to find any dependency on
the weather, etc ... I took car to the dealership and they didn't find
anything wrong with break system.

Did anybody have similar problem? I hope it will not happen again but
at 100 km/h ....

The service dept must be staffed with morons. I had exactly the same thing
happen with my 01 S40 and it was a leaky vacuum hose to the booster or the
device that maintains a vacuum for the booster. What happens is the leak
bleeds off the vacuum overnight (at least that's how it was in my case) so
in the morning - no power brakes. Letting the engine run for a while before
taking off will get the system working again. Since this is a slow leak, it
is unlikely that it will fail suddenly. Since this is Volvo, the fix wasn't
as simple as a mere hose replacement but rather some vacuum brake system
assemby. I might be wrong about this as I don't have the repair ticket
available right now but there may be a Volvo Technical Service Bulletin on
this.

 

[techie]

I think that you've solved the mystery! I now realize that it happens
if I start driving immediately after starting the engine. Hopefully now
I could reproduce it at the dealership.

I am surprised that Volvo service didn't know this. Car is still under
warranty and they are probably not too keen on doing repairs. It's
just too bad that their profit considerations taking over the safety
concerns.

Thanks.

 

[Lloyd Wells]

I think that you've solved the mystery! I now realize that it happens
if I start driving immediately after starting the engine. Hopefully now
I could reproduce it at the dealership.

I am surprised that Volvo service didn't know this. Car is still under
warranty and they are probably not too keen on doing repairs. It's
just too bad that their profit considerations taking over the safety
concerns.

Thanks.

I take my S40 to an independent shop and he didn't have any problem
identifying the problem. You'll probably need to leave it overnight so they
can see for themselves what's wrong. I took the precaution of putting a note
in plain view that the power brakes don't work just so the tech doesn't
drive it into a wall expecting it to stop normally!